Sounding Reference Signal Multiplexing for Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in LTE-A, transmitting sounding reference signals (SRS) using multiple antennas is inefficient due to power amplifier restrictions and resource allocation challenges, limiting the ability to utilize wider frequency bands effectively.
Innovation Solution
The method involves generating and multiplexing SRS based on a Repetition Factor (RPF) corresponding to the number of transmission antennas, using code division multiplexing and frequency division multiplexing techniques to allocate cyclic shift values and frequency resources, allowing for efficient transmission across multiple antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple sounding reference signals are transmitted using multiple antennas, then the frequency band utilization is improved, but the power amplifier efficiency deteriorates due to restrictions on simultaneous transmissions
Solution Approach 1:
The patent segments the transmission of multiple SRS signals by allocating different antenna ports to different subsets of frequency resources. Instead of transmitting all SRS signals simultaneously across the entire bandwidth, each antenna port transmits its SRS on a specific subset of resource blocks, dividing the frequency domain into non-overlapping segments for different antennas.
Solution Approach 2:
The patent introduces frequency domain segmentation as an additional dimension for multiplexing SRS signals from multiple antennas. By organizing SRS transmissions across different frequency subsets rather than only in the time domain or using code division, the system efficiently utilizes the frequency dimension to accommodate multiple antenna transmissions without power amplifier conflicts.
2Measurement precision
If multiple sounding reference signals are transmitted simultaneously, then the channel state information acquisition is improved, but the resource allocation complexity increases due to power amplifier restrictions
Solution Approach 1:
The patent segments the frequency resources into distinct subsets assigned to different antenna ports, which simplifies resource allocation by providing clear, non-overlapping frequency regions for each antenna. This segmentation approach reduces the complexity of managing simultaneous transmissions compared to unsegmented resource allocation.
Solution Approach 2:
The patent applies local quality by assigning specific frequency subsets to specific antenna ports, allowing each antenna to transmit its SRS signal on optimized frequency resources tailored to its characteristics. This localized allocation simplifies the overall resource management while maintaining precise channel state information for each antenna.
3Quantity of substance
If the Repetition Factor is increased to accommodate more transmission antennas, then the number of multiplexed SRS signals is improved, but the frequency resource consumption increases
Solution Approach 1:
The patent utilizes the frequency domain as an additional dimension for multiplexing SRS signals by dividing the available bandwidth into multiple subsets, each assigned to a different antenna port. This frequency domain segmentation allows multiple SRS signals to be transmitted simultaneously without requiring proportional increases in total frequency resource consumption, as each subset efficiently utilizes its allocated portion.
Data Source
AI summary
The present invention relates to a method in which a user equipment transmits a plurality of sounding reference signals to a base station in a wireless communication system. More particularly, the method comprises the steps of: generating a plurality of sounding reference signals on the basis of repetition factors (RPFs) corresponding to the number of transmitting antennas; multiplexing the plurality of sounding reference signals to a frequency domain in the same OFDM symbol or SC-FDMA symbol on the basis of a transmitting antenna index; and transmitting the multiplexed sounding reference signals to the base station using a plurality of transmitting antennas.